A muffler is often used to attenuate acoustic waves (e.g., sound) generated by a machine, such as for example, an engine or a compressor. In an HVAC system, an HVAC compressor is one of the major acoustic wave sources. A muffler can be used with the compressor to attenuate the acoustic waves generated by the compressor, which may help reduce an operational sound of the HVAC system. Reducing operational sound may be desirable, for example, in a school, during nighttime, or in other situations.